a) Field of the Invention
The invention relates to a barrage jammer with contoured amplitude and an associated method for barrage jamming with contoured amplitude.
b) Description of Related Art
Wireless devices are widely used in today's society. One of the most common wireless devices is the cellphone, but there are a variety of other examples such as cordless phones, walkie talkies, tablets, radios, etc.
The art of jamming wireless devices has been known for a long time. It initially was applicable to military communications, but has now gained greater traction in the civilian arena.
In order to jam wireless devices, there is a definition of the target area for the affected wireless devices as well as the area where the jammer should not have an impact. Although jamming is not an exact science, the goal is to deliver a dominant amount of RF jamming power within the target area while trying to minimize the bleed of this power in the area where the jammer should not have an impact. In the military arena, this bleed is typically not as important as it is in the civilian arena. For civilian purposes, the bleed of RF signals outside the target jamming area is typically as important as the delivery of jamming power within the target area.
There are three general jamming techniques that have been used in the prior art.
The first technique is called “spot jamming” and it utilizes a CW or slightly spread signal that targets the frequency used by the wireless device for communication. This form of jamming is fairly easy to implement, but has fallen out of favor because it is easy to defeat using either frequency hopping or direct sequence spread spectrum techniques.
The second technique is called “barrage jamming” and it utilizes jamming of the entire band (or bands) that the target wireless device can use for communication. There are two basic problems with barrage jamming. First, it is very inefficient because it spreads the RF power across the entire communication band rather than focusing it on the frequencies used by the target wireless device. Second, it exacerbates the bleed problem because all of the power unnecessarily delivered in the band (outside of the target wireless device frequency) will unnecessarily bleed and possibly affect other wireless devises outside of the target area.
The third technique is called “targeted jamming” and it uses advanced RF or sophisticated radio techniques to more precisely target the wireless device. An example of the RF approach is disclosed in U.S. Pat. No. 9,258,078 which teaches the use of beam forming techniques to direct the jamming signal to the target while reducing its impact in other areas. An example of the sophisticated radio approach is disclosed in U.S. Pat. No. 9,749,085 which teaches the use of a Software Defined Radio (SDR) to detect the target communication signals and produce similar signals to spoof the receiver on the target device.
The problem with the targeted jamming approaches is that in order to solve the problems with barrage jamming, these new approaches require a great deal of additional complexity as well as the associated costs.
What is needed is a better way to perform barrage jamming that addresses the problems of inefficient spectral targeting as well as bleed.